# 如果有一堆文本，你想看一下是否有你目前关注的 关键词
vowels = ['a', 'e', 'i', 'o', 'u']
word = input("提供一个单词来搜索元音: ")
found = []
for letter in word:
    if letter in vowels:
        if letter in vowels:
            if letter not in found:
                found.append(letter)
for vowel in found:
    print (vowel)
